5 The Arsenal Roentgenography (X-Ray) Fluoroscopy Cardiac MRI (?)EchocardiographyTTE will often best allow optimal Doppler anglesTEE will often best allow optimal direct visualizationIntangibles

6 The Main Characters Mechanical ValvesBall-cage (Starr-Edwards)Tilted-disc (Bjork-Shiley, Medtronic-Hall)* Note: the convexoconcave version of the Bjork-Shiley valve earned a bad name due to cases of strut fracture and disc embolizationBileaflet (St. Jude, Carbomedics)All valves are sized by diameter, mmO’Neill NEJM 1995

7 Main Characters, Part DeuxBioprosthetic ValvesStented: Carpentier-Edwards, Hancock, Ionescu-Shiley, St. Jude MosaicStentless: Biocor.Homografts/autografts: may not be able to detect noninvasivelyAlso sized by diameter, mmHancockMosaicStentless porcine

8 Unveiling the arsenal Old School: RoentgenographyMechanical and many stented bioprosthetic valves are radiopaque, allowing determination of valve type and position on chest X-ray.May be used to assess for device fracture in some casesStarr-Edwards valve seen in aortic positionin From Nery, Heart 2004

9 Up a Notch: FluoroscopyBest methodology to assess mechanical leaflet motion due to outstanding spatial and temporal resolution.May be used to assess stability of valve ring with the cardiac cycleMay optimally position angle to best assess subtle fractureO’Neill NEJM 1995

14 Echocardiography Transthoracic TransesophagealAllows assessment of valve area and regurgitation via Doppler, which is generally adequate to exclude significant obstructive or regurgitant change. Flow velocity is the crucial measurement.Inadequate to assess infection or small structural changes (e.g. strut fracture, small vegetation, paravalvular leak)TransesophagealIdeal for visual inspection of valve apparatus and seating; may not accurately quantify valve flow velocities. May directly measure aortic valve area via planimetry

15 Echo by valve position Aortic Mitral Tricuspid PulmonicAccurate TTE assessment relies on accurate Doppler assessments in multiple viewsOften many TTE views partially obscured by shadowing. Often TEE required to view leafletsMitralAmong the best positions for TTE visualization, usually able to see leaflets via apical viewsTricuspidAlso usually adequately visualized by TTE directly and via DopplerPulmonicRarest position for valve replacement. Difficult to visualize for both TTE and TEE, no clear advantage

16 Aortic ProsthesesFocus on Doppler imaging of aortic outflows to determine mean and peak gradientsCan identify prosthesis type by direct visualizationAs with all prostheses, need to know their SIZE to allow assessment of normal vs. pathologically increased transvalvular gradient.Size varies from mm in diameterNormal gradients for each valve type and size may be found on reference tables

26 Peak gradient 17mm- need valve size and ideally baseline gradient at time of valve implantation to assess for normal valueMay also use continuity equation with measurement of LVOT to calculate effective aortic valve area

75 Summary Valve type and position often easily determined on CXRFluoroscopy optimal for assessing mechanical valve leaflet motion, unable to see bioprosthetic leafletsTTE may identify flow velocities and gross structure, best suited for MVR and exclusion of obstruction due to good Doppler views. Doppler velocities and valve gradients are likely better than calculation of valve area due fewer variablesTEE allows better visualization of smaller structural changes, vegetations, and paravalvular leaks. It is the study of choice for concerns of endocarditis in any prosthetic valve.CMR limited role and not generally used to assess prosthetic valves.